The present invention is directed to a system and method for removing resin bleed from an encapsulated electronic component and more particularly to a system and method for removing resin bleed from the encapsulated electronic component as the component continuously moves along through the system.
Since the early 1970s delicate electronic components (such as integrated circuit chips) have been encapsulated in electrically insulating bodies from which only contact elements necessary to communicate to others portions of a completed circuit protrude. It is particularly advantageous to create such insulating bodies by dipping the component to be protected into a thermoset plastic resin. The resin, however, often coats more than the electronic circuit or drips onto the leadframe of the electronic circuits. In other words, this resin ends up coating part of the leads for the electronic circuit, and such excess resin is referred to herein as "resin bleed". Resin bleed must be removed from the leads prior to any later manufacturing processes, such as the electroplating of the leads.
Various methods for removing resin bleed have been tried. Chemical deflashing uses a chemical solution which will dissolve or otherwise remove the resin bleed from the leads. Traditionally, M-Pyrol has been used in chemical deflashing. Use of M-Pyrol, however, has been known to cause many in-house fires due to its flammability and high operating temperatures. Therefore, chemical deflashing has dangerous side effects.
Another type of deflashing equipment has been used in which a high pressure liquid with a mixture of fine glass or sand media is sprayed at the leadframe in order to remove the resin bleed. This type of deflashing, which is known as "media deflashing" or "media blasting", however, also presents problems because the media gets imbedded in the leadframe, the media is expensive and the solution with the media is a contaminated solution which must be properly discarded. Once the media deflashing equipment was automated to a production capacity of approximately 700 cut strips per hour the use of M-Pyrol was significantly reduced.
During the 1980's, both chemical deflashing and media blasting were used either alone or in combination to remove resin bleed. In both type of systems, a significant amount of handling is required because the encapsulated electronic components are batch loaded into either type of system. Once the components are processed in such a system they are then generally taken to rinse stations and drying stations. This processing is therefore slow and requires human intervention to load the leadframes into the various other process stations.
It is therefore a principal object of the present invention to provide an in-line system and method for removing plastic resin bleed from a metallic leadframe of an encapsulated electronic component following the molding of the component without the need for human intervention.
It is a further object of the present invention to provide a system and method for continuously processing a succession of encapsulated electronic components in order to remove resin bleed from their metallic leadframes.
A still further object of the present invention is to provide a system and method for removing resin bleed from encapsulated electronic components which can be used either in-line with other production equipment or as a stand alone system.